Digestion as environmental aid

Sunday

Mar 3, 2013 at 6:00 AMMar 3, 2013 at 6:44 AM

By Lynne Klaft CORRESPONDENT

The domed building on the Jordan Dairy Farm in Rutland turns cow manure and food waste into liquid fertilizer and electricity. It’s called a digester, and it’s the first of its kind in the Commonwealth.

It’s clean, it’s quiet and there are no discernible odors. With more than 5 million tons of waste being disposed of yearly in Massachusetts — 25 percent of which is organic matter — the digester is the state’s answer to recycling organic materials, food and yard waste.

The state is proposing the construction of a digester on state-owned land and is looking at three sites in Massachusetts, one of which is MCI Shirley.

“Our goal is to divert 350,000 tons a year from the waste stream by 2020. There will be more space left in our landfills, we can increase energy production and there are benefits,” said Catherine Finneran, director of the state Department of Environmental Protection’s Clean Energy program, while speaking to Lancaster residents at a recent public information meeting. Part of the prison is in town and would be affected by any construction there.

The benefits Ms. Finneran listed include production of heat and electricity, lengthening the life of existing landfills, production of fertilizer and soil amendments, savings on waste disposal costs, reducing greenhouse gas emissions, and decreasing the use of fossil fuels.

The state plans to change regulations to remove siting obstacles for the construction of digesters and improve the collection and processing infrastructure for organic materials, and will have an organics ban regulation in 2014 that will mandate large generators of organic materials, such as hospitals, universities, prisons and food processing plants, to recycle waste using digesters instead of dumping it in landfills.

Jordan Farm receives 65 percent of its organic waste from an organics recovery facility in the Boston area. It is blended with manure from the more than 500 cows on the farm.

Four major food companies — H.P. Hood & Sons, Cabot Creamery, Kayem Foods and Cains Foods — agreed to provide the farm with food scraps and byproducts instead of sending it to disposal.

On average, the farm receives two tanker trucks daily filled with the food waste products. The material is pumped directly into a receiving tank, where it is mixed with cow manure that is piped from the cow barns into the tank.

The blended organic wastes are then pumped into the 500,000 gallon digestion tank.

“And that’s where the magic happens,” said Shannon Carroll, facility manager at Casella Organics, the company partnering with farms to operate digesters under the name AGreen Energy. “Bacteria breaks down the material and produces methane. We have a 300-kilowatt engine to make electricity, some of which is used to power the farm and the digester; the rest is sent to the grid.”Liquid fertilizer is also produced and stored in a million-gallon tank and a lagoon, waiting to be spread during the growing season. Jordan Dairy Farm also grows hay and feed corn, and the fertilizer is spread on the crops every month or so.

Dairy farmer Randy E. Jordan said that the liquid fertilizer that is produced means less money spent on commercial fertilizers.

“And the electricity powers our milking machines, lights, cooling systems and our farmhouse needs. We started a co-op about four years ago with AGreen. The business plan says that all five farms (in the co-op) will have a digester. One of the farmers went to Germany to see one running. They’ve had them there for years now. Farmers have struggled with low milk prices, and you have to have something else.

“You don’t get rich milking cows, but we love what we do; we can be good conservationists and still work the land. And the fertilizer that we spread, well, on the Fourth of July there are less complaints of the smell,” said Mr. Jordan.

Ms. Carroll runs the digester, makes sure the organics blend is just right, adjusts the delivery schedules, repairs machinery and keeps tabs on all parts of the facility on a 24-hour, 7-days a week schedule.

Much of the monitoring is done by computer, and she can adjust flows and keep tabs on temperature and build-up of excess gas even when she is at home. The computer will set off alarms and signal her when adjustments or repairs need to be done.

The state is doing a feasibility study for an on-site location for a digester and plans to choose a site and contractor to build it by December. The digester will be up and running by 2015.